Solidify a UV sphere that has a part transparent material?
I found a solution:

First resize the UV sphere so it is a little bit smaller than the surface of the water and UV unwrap it. (Since I am using a distorted map of the earth that is meant for a sphere, sphere projecting the image will work perfectly.)

Second add a subdivision surface (more subdivides=better resolution) and a displacement map to the sphere. Lower the displacement strength down to .1 or .2 and Set the Texture Coordinates to UV:



Next add a new texture in the displacement modifier and edit the texture under the texture panel. Open the black and white image (Black=Transparent, white=terrain) of your choice and adjust the brightness to the desired amount. (Brightness changes how much terrain pops out.)



Finally, change the material to have a mix shader of diffuse and transparent, factored by the same black and white image used for the displacement:



Result (Not the best result but does work):